Diaphragm blades dont move

[mrpenguin]

I dont understand this, maybe i am just an idiot but when I put a lens on my camera, adjust the aperture to lets say f2.8, take the lens off and look at the diaphragm blades it is small, as if at f22. This is on all my lenses I have, the diaphragm blades when I look at them when the lens is off my camera is always at f22. I dont get it ???

I am using a D7000

[donoreo]

The lens will go to a default. It only adjusts to the aperture you set when you use the DOF preview button or when the shutter button is pressed. I thought most went to wide open, but I guess not.

[mrpenguin]

Ok, thanks .... so once the shutter button is pressed the Diamhragm blades open or close and then after the picture is taken it goes back to the smallest opening again ?

[greenwing]

Nikon lenses close down to the aperture set on the aperture ring, or to the smallest aperture in the case of G-type lenses (with no aperture ring), when off the camera, by a spring load. When mounted on the camera, they open to their widest aperture by pressure of a camera lever against the lens spring, for metering and focusing. When the exposure is made, the camera's lever moves to the taking aperture position, the lens spring moves the blades to the taking aperture, the shutter opens and closes, and the camera's lever moves back to wide open, forcing the lens wide open again. Take the lens off the camera, and that darned spring closes the aperture down again.

In other words, it's normal, don't panic.

Chris

[mrpenguin]

Thank you so much !